Inlet cannon with replaceable bearing shoe for billet-piercing mills



KELSO REPLACEABLE BEARING T-PIERCING MILLS BILLE ed April 8, 1948 J. W. CANNON WITH OE FOR Fil INLET July 15, 1952 NY M F& t. I

N Erl Inventor JOHN W K6250,

' filial/W064 Patented July 15, 1952 INLET CANNON WITH REPLACEABLE BEAR- ING SHOE EORBILLET-PIERCING MILLS John W. Kelso, Clairton, Pa., assignor to United States Steel Company, a

Jersey corporation of New Application April 8, 1948, Serial No. 19,861 g 5 Claims.

This invention relates to a piercer mill used in making seamless tubes and, in particular, to the entering guide or inlet cannon thereof.

Inlet cannons for piercer mills have heretofore been composed of a onepiece tubular casting. This construction has several disadvantages. The bottom of the core is subject to severe wear by rubbing of the billet as it is rotated on its own axis during piercing. This makes it necessary to reline and machine the bore from time to time or replace the entire cannon. Such repair or replacement is relatively costly. The removal of the cannon and the resetting thereof, furthermore, take considerable time and involve a loss of production. The continuous cylindrical wall of the bore affords a bearing surface which the rotating billet tends to climb, thus causing objectionable vibration and gyration. Scale detached from the billet lodges in the cannon and may be carried forward into the piercer-mill pass where it is likely to become embedded in the tube. I have invented an improved cannon which effectively overcomes the aforementioned disad vantages. In a preferred embodiment, I provide a box-like tubular housing having a bottom, side walls and an arched or semi-cylindrical top. .A bearing shoe is removably disposed on the bottom of the housing and has a longitudinal trough of the same radius as the top, adapted to receive and support the billet as it advances while rotating. The surface of the shoe is relieved at the sides of the trough, whereby vibration and gyration of the billet are reduced. The housing base has an abutment with an undercut portion which holds the shoe in place. The sides of the housing have outlet openings permitting the es.- cape of scale from the billet.

A complete understanding of the invention may be obtained from the following detaileddescription which refers to the accompanying drawings illustrating the present preferred embodiment.

In the drawings:

Figure 1 is an end elevation looking at the entering end;

Figure 2 is a central longitudinal section taken along the plane of line 11-11 of Figure 1;

Figure 3 is a horizontal section taken along the plane of line III-III of Figure l; and

Figure 4 is a partial transverse section to enlarged scale.

Referring in detail to the drawings, the inlet cannon there shown is a tubular box-like casting I 0 having a bottom ll, sides l2 and an arched semi-cylindrical top E3. The cannon is mounted in the usual position ahead of the pass of a piercer mill, as shown in Findlater- Patent No.

2,141,131, issued December 20, 1938, being secured facilitate the entry of billets advancing into the piercing-mill pass.

The bottom H. of the cannon is machined on the inside to provide a smooth surface It -ac-' commodating a shoe or replaceable liner platexlilcoextensive therewith, the upper face of which has a longitudinal trough 19 therein. Grooves or recesses Hi are cored at the ends of the bottom ll so as to provide chip clearance when machining surface IS. The trough is cylindrical, at least adjacent the median longitudinal plane, and has substantially the same axis and radius as the interior of the arched top 13. The sides of the trough are designated lll The exit end of the bottom I I has an abutment 2D trough-shaped on top conforming to the curvature of the trough in shoe IS. The abutment 20 is undercut, as at 2|, on the inner side, and the coacting end of the shoe 1!! is beveled, as at 22, to conform-thereto. By this construction, the shoe is held firmly in place on the bottom I l by the advancing billets.

A retaining flange 23 extending upwardly from the'bottom H at the entry end also serves. to confine the shoe in position. This flange has an upwardly sloping top 24 and the adjacent end of the shoe likewise slopes upwardly, as at 25, to guide the entering billets up into the trough 19 in the shoe. Longitudinal slots or grooves 26 in the bottom II at the sides of the surface l8 accommodate tongues or keys 2'! extending downwardly from the edges of the shoe. The trough 19 of the shoe may have a lining of wear-resistant metal 28 applied thereto in any desired manner.

It will be evident that the trough us formed in the shoe l9 and the continuation thereof in the abutment 20 at the exit end, together with the semi-cylindrical top H 3, constitute a substantially complete tube and guide the entering billet accurately toward the piercer point in the pass of the mill. When the shoe has been worn to such a condition that it is no longer serviceable, it may be lifted out and replaced by a new one with little or no delay and without stopping the succession of heated billets being fed through the piercer mill. Since no bolts or other fasteners are required to hold the shoe in position, its removal and replacement may be accomplished very quickly. The shoe sustains by far the greater portion of the Wear to which the cannon as a whole is subject and the life of the tubular casting is, therefore, prolonged almost indefinitely, the bottom ll being replaced whenever necessary. Wear of the trough in abutment 20 at the exit end of the cannon is not serious. The shoe l9 supports the billet properly for entry into the piercer mill, even after the surface of the trough in abutment 20 has been worn down below the shoe 19.

The trough 19 in the surface of the shoe I9 is relieved gradually adjacent the sides I9 as indicated at 29. In those regions, an ogee curve merges with the cylindrical surface of the bottom of the trough. The relief thus afiorded the contact between the billet, indicated in chain lines at 30, and the surface of the shoe, limits the tendency of the billet to climb as it rotates about its own axis and thus reduces the vibration and gyration to which piercer-mill cannons as heretofore constructed have been subjected.

Spaced openings or Windows 3| are formed in the sides I2 of the cannon I!) to permit the escape of scale fragments detached from the billet as it rotates while advancing into the pass. These openings reduce the likelihood that such fragments will be carried into the pass and become embedded in the tube.

It will be apparent from the foregoing that the invention provides an inlet cannon having numerous advantages over such structures as made heretofore. As already pointed out, the provision of a replaceable shoe permits renewal of the part which receives the brunt of the wear without removing or scrapping the cannon as a Whole, in addition to avoiding the loss of time incident to replacement. The cost of my improved cannon is not greatly in excess of that of the conventional guide and it may be installed in the same manner and without requiring any change in the operation of the mill.

Although I have illustrated and described but a preferred embodiment of the invention, it will be recognized that changes in the details thereof may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. An inlet cannon adapted to be mounted at the entrance end of a piercer mill, comprising an elongated box open at both ends and including a flat bottom, spaced side walls extending upwardly from said bottom and a semi-cylindrical top springing from said side walls, and a fiat-bottomed shoe substantially coextensive with the bottom of said box and removably disposed thereon, said shoe having a longitudinal trough of arcuate section in the top thereof, the semicylindrical top of the box and the trough in the shoe being substantially coaxial, having substantially equal radii and constituting together with said side walls a substantially complete tube alined with the mill pass and effective to guide an advancing billet centrally thereinto, the top of the shoe being relieved on each side of the trough thereby limiting the tendency of the billet to climb on rotation.

2. An inlet cannon as defined by claim 1 characterized by the bottom of said box havingan abutment at the exit end undercut on the inner side and said shoe being shaped at the exit end to fit snugly against the abutment.

3. An inlet cannon as defined by claim 1 characterized by the relieved sides of the trough being of ogee shape in section.

4. An inlet cannon as defined by claim 1 characterized by said side walls having escape ports for scale spaced therealong.

5. An inlet cannon'as defined by claim 1 characterized by the contacting surfaces of said shoe and box having a slot in one and a tongue on the other fitting in said slot.

JOHN W. KELSO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,039,169 Kearns et al. Apr. 28, 1936 2,141,131 Findlater Dec. 20, 1938 2,245,656 Engelbaugh et al. June 17, 1941 2,277,029 Anater Mar. 24, 1942 

